1. Field of the Invention
This invention relates to a combined fire ring and carbon-scraping cylinder insert which simplifies engine assembly.
2. Description of the Prior Art
In high pressure internal combustion engines an effective long lasting seal at the upper end of a cylinder must be provided between the engine block and the cylinder head. In some engine designs a cylinder sleeve lines the cylinder with the top of the sleeve level with the engine block at the top of the cylinder. In engines having such a sleeve, the seal is actually formed between the cylinder head and the cylinder sleeve. Whether the seal is between the cylinder head and the engine block or between the cylinder head and the cylinder sleeve, it must be capable of withstanding both high temperatures and pressures. One arrangement for providing this seal is described in U.S. Pat. No. 3,586,338 to Ernest P. Miklau and John R. Crowe. The engine block or cylinder sleeve is provided with a bead raised above the surface of the block or sleeve around the perimeter of each cylinder. A flat annular fire ring is positioned on the engine block or cylinder sleeve during assembly to surround the cylinder at its upper end and to rest on the bead. The cylinder head is provided with grooves corresponding to the raised bead around the perimeter of each cylinder. After the fire rings are positioned, the cylinder head is placed on the block and fastened to the block securely. The bead on the block or cylinder sleeve forces a portion of the metal fire ring to conform to the contours of the groove in the cylinder head and a seal is formed.
Occasionally, problems have arisen during the fastening of the cylinder head to the engine block when a fire ring is positioned improperly or is moved out of position during the assembly process. If the fire ring's position is not corrected, an imperfect seal may be formed when the cylinder head is fastened onto the engine block or other engine parts, such as the cylinder sleeve, may crack. Apart from the possibility of defective seals or damage to engine parts, the prior art arrangement requires additional time-consuming effort to insure that each fire ring is placed in the precisely correct position to provide an effective seal.
Within an engine cylinder, carbon deposits form on piston walls above the piston rings and it is desirable to remove such deposits on a regular basis to prevent their accumulation. To accomplish this, an annular insert has been provided in a recess in the top of each cylinder, as illustrated in U.S. Pat. No. 3,489,130 to Harry L. Polidan and Norman M. Packard. The insert is positioned to scrape carbon deposits from the piston as the piston moves within the cylinder.
By the present invention the above-mentioned problems of the prior art have been eliminated. The assembly of the engine has been facilitated, assembly time reduced, and effective seals ensured. Moreover, the unitary structure of this invention not only achieves these desirable results with respect to effective seals and ease of assembly but also functions effectively as a carbon scraping insert.
Accordingly, it is an object of this invention to provide a unitary structure which is automatically positioned properly and securely to form a seal.
It is also an object of this invention to provide a unitary structure for forming a seal between the cylinder head and an engine block or cylinder sleeve which is easy to assemble.
A further object of this invention is to provide a unitary structure which combines the functions of a fire ring and a cylinder insert.